RESUMO
BACKGROUND: Approximately 100 small supernumerary marker chromosomes (sSMCs) with a non-α-satellite neocentromere structure have been reported in the literature. Of the few derived from chromosome 13, five have consisted of inverted duplicated segment 13q32qter. CASE REPORT: We herein describe the sixth case, characterized by genome wide SNP array, conventional cytogenetics and FISH studies. The de novo occurrence of the marker, the poor prognosis and the presence of hemangiomas are consistent with previous cases. CONCLUSION: We hereby expand the clinical spectrum of this rare cytogenetic disorder and suggest a possible mechanism for the pathogenesis of associated congenital vascular malformations.
Assuntos
Anormalidades Múltiplas/genética , Cromossomos Humanos Par 13 , Neoplasias de Cabeça e Pescoço/genética , Hemangioma/genética , Laringomalácia/genética , Defeitos do Tubo Neural/genética , Tetrassomia/patologia , Anormalidades Múltiplas/patologia , Anormalidades Múltiplas/fisiopatologia , Insuficiência de Crescimento , Marcadores Genéticos , Neoplasias de Cabeça e Pescoço/patologia , Neoplasias de Cabeça e Pescoço/fisiopatologia , Hemangioma/patologia , Hemangioma/fisiopatologia , Humanos , Lactente , Cariotipagem , Laringomalácia/patologia , Laringomalácia/fisiopatologia , Masculino , Defeitos do Tubo Neural/patologia , Defeitos do Tubo Neural/fisiopatologia , Morte Súbita do Lactente/diagnóstico , Tetrassomia/fisiopatologiaRESUMO
Rhabdomyosarcoma is the most common pediatric soft tissue malignancy. Two major subtypes, alveolar rhabdomyosarcoma and embryonal rhabdomyosarcoma, constitute 20 and 60% of all cases, respectively. Approximately 80% of alveolar rhabdomyosarcoma carry two signature chromosomal translocations, t(2;13)(q35;q14) resulting in PAX3-FOXO1 fusion, and t(1;13)(p36;q14) resulting in PAX7-FOXO1 fusion. Whether the remaining cases are truly negative for gene fusion has been questioned. We are reporting the case of a 9-month-old girl with a metastatic neck mass diagnosed histologically as solid variant alveolar rhabdomyosarcoma. Chromosome analysis showed a t(8;13;9)(p11.2;q14;9q32) three-way translocation as the sole clonal aberration. Fluorescent in situ hybridization (FISH) demonstrated a rearrangement at the FOXO1 locus and an amplification of its centromeric region. Single-nucleotide polymorphism-based microarray analysis illustrated a co-amplification of the FOXO1 gene at 13q14 and the FGFR1 gene at 8p12p11.2, suggesting formation and amplification of a chimerical FOXO1-FGFR1 gene. This is the first report to identify a novel fusion partner FGFR1 for the known anchor gene FOXO1 in alveolar rhabdomyosarcoma.
